REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Anti-human CXCR5 BUV395 (final dilution 1:80)	BD Biosciences	Cat# 740266; RRID: AB_2740008
Anti-human CCR4 PE-CF594 (final dilution 1:40)	BD Biosciences	Cat# 565391; RRID: AB_2739215
Anti-human CCR6 BV480 (final dilution 1:66)	BD Biosciences	Cat# 566130; RRID: AB_2739529
Anti-human CXCR3 BV510 (final dilution 1:40)	Biolegend	Cat# 353726; RRID: AB_2563642
Anti-human IgM BUV496 (final dilution 1:200)	BD Biosciences	Cat# 750366; RRID: AB_2874541
Anti-human CD4 BUV563 (final dilution 1:200)	BD Biosciences	Cat# 612912; RRID: AB_2739451
Anti-human CD11c BUV661 (final dilution 1:100)	BD Biosciences	Cat# 612967, RRID: AB_2870241
Anti-human IgD BUV737 (final dilution 1:200)	BD Biosciences	Cat# 612798; RRID: AB_2738894
Anti-human CD45RA BUV805 (final dilution 1:200)	BD Biosciences	Cat# 742020; RRID: AB_2871317
Anti-human CD138 BV605 (final dilution 1:50)	Biolegend	Cat# 356520; RRID: AB_2562862
Anti-human ICOS BV650 (final dilution 1:50)	Biolegend	Cat# 313550; RRID: AB_2749929
Anti-human CD20 BV750 (final dilution 1:200)	BD Biosciences	Cat# 747062; RRID: AB_2871819
Anti-human CD38 BV785 (final dilution 1:100)	Biolegend	Cat# 303530; RRID: AB_2565893
Anti-human CD8α PerCP-eFluor710 (final dilution 1:200)	Invitrogen	Cat# 46-0086-42; RRID: AB_2848331
Anti-human CD27 PE-Cy5 (final dilution 1:50)	Invitrogen	Cat# 15-0279-42; RRID: AB_10717249
Anti-human CD19 PE-Cy5.5 (final dilution 1:200)	Invitrogen	Cat# 35-0198-42; RRID: AB_11218903
Anti-human CD11b Alexa Fluor 700 (final dilution 1:100)	Biolegend	Cat# 301356; RRID: AB_2750075
Anti-human PD-1 PE-Cy7 (final dilution 1:50)	Biolegend	Cat# 329918; RRID: AB_2159324
Anti-human/mouse BCL6 Alexa Fluor 647 (final dilution 1:50)	BD Biosciences	Cat# 561525; RRID: AB_10898007
Biological samples
Human FNA	Perelman Center for Advanced Medicine	N/A
Human PBMC	Perelman Center for Advanced Medicine	N/A
Human pediatric tonsils	Children’s Hospital of Philadelphia	N/A
Chemicals, peptides, and recombinant proteins
Fixable viability dye eFluor 780	Invitrogen	Cat# 65086518
Recombinant RBD	Norbert Pardi	N/A
Recombinant Spike-Biotin	R&D Systems	Cat# BT10549-050
Recombinant PR8 HA	Norbert Pardi	N/A
Streptavidin BV421	Biolegend	Cat# 405225
Streptavidin Alexa Fluor 488	Biolegend	Cat# 405235
Streptavidin Alexa Fluor 647	Biolegend	Cat# 405237
EZ-LinkTM Micro Sulfo-NHS-LC-Biotinylation Kit	Thermo Fisher Scientific	Cat# 21935
EZ-Link™ Sulfo-NHS-LC-Biotin, No-Weigh™ format (included in EZ-LinkTM Micro Sulfo-NHS-LC-Biotinylation Kit)	Thermo Fisher Scientific	Cat# A39257
ZebaTM spin desalting columns (included in EZ-LinkTM Micro Sulfo-NHS-LC-Biotinylation Kit)	Thermo Fisher Scientific	Cat# 89889
BupH phosphate-buffered saline (included in EZ-LinkTM Micro Sulfo-NHS-LC-Biotinylation Kit)	Thermo Fisher Scientific	Cat# 28372
FoxP3/transcription factor staining buffer set	ThermoFisher Scientific	Cat# 00-5523-00
ACK lysis buffer	Gibco	Cat# A1049201
DMSO	Sigma	Cat# D2650
FBS	Corning	Cat# 35-010-CV
EDTA	Invitrogen	Cat# 15575-038
PBS	Corning	Cat# 21-031-CV
Glutamax	Gibco	Cat# 35050-061
Penicillin-streptomycin	Gibco	Cat# 15140-122
RPMI	Gibco	Cat# 22400-089
Brilliant Stain Buffer	BD BioSciences	Cat# 563794
0.9% Buffered lidocaine	Hospital of the University of Pennsylvania	N/A
4% Chlorhexidine gluconate	SC Johnson	Cat# 134439
16% Paraformaldehyde	Electron Microscopy Sciences	Cat# 15710
Molecular biology grade water	Corning	Cat# 46-000-Cl
Software and algorithms
FlowJo v10	FlowJo LLC	RRID: SCR_008520
Other
UltraComp eBeadsTM compensation beads	Thermo Fisher	Cat# 01-2222-42
Spectral cytometer	Cytek	Aurora spectral analyzer (5 lasers, 64 detectors)
Ultrasound machine	Phillips	EPIQ ELITE or IU222
Ultrasound probes	Phillips	L15-7io or C8-5